- Definitive surgical treatment must be either mastectomy, or breast conserving surgery with axillary lymph node dissection for operable breast cancer (T1-3, Clinical N0-1, M0). Margins of resected specimen from definitive surgery must be histologically free of invasive adenocarcinoma and Ductal Carcinoma In Situ (DCIS). Lobular carcinoma in-situ does not count as a positive margin.